The object of the present invention patent is a variable flow valve, preferably applicable in offtake branches for ejection of surplus cephalorhachidian fluid existing in the ventricles of the brain in patients affected by hydrocephalus.
As is known by medical pathology this type of disease is characterized by an increase in the pressure of the cephalorhachidian fluid existing in the ventricles of the brain. This pressure increase is due to a pathological occlusion of the natural paths that permit regulation of this pressure. In these cases it is essential to surgically intervene to form auxiliary channels for the surplus fluid, otherwise the brain will suffer severe and irreparable injuries.
Naturally these offtake branches must be maintained functionally in place by the patient because of the cyclic nature of this abnormal phenomenon, therefore it becomes necessary to use a valve for regulation of ventricular pressure.
In this regard modern surgical engineering has only an extremely limited number of valves to offer. The most well known and used of them is the diaphragm valve, but this valve is subject to a number of flow and tension problems.
This valve, in fact, is manufactured case by case and set for a specific limit pressure that can differ from one patient to another.
This means that increases in ventricular pressure that stay below this limit cannot be discharged. This results in a period of brain suffering that can only be relieved when the pressure exceeds the valve threshold setting.
This type of valve is also easily subject to occlusions and other similar troubles that quickly make the appliance unserviceable.
Other by-pass means have also been developed, such as constant flow systems which are efficient for small pressure variations but which are absolutely inadequate for strong jumps in pressure which require immediate and abundant external discharge.